You're not going to give up on your plans to diaper Madison--especially now that she will definitely be needing them--so you need to get past her father, but this conflict with him is too interesting to just eliminate. You decide to just tilt the scales in your favor a good bit.
You turn around on the step, look down at Andrew's wife, and say,
~You are completely in favor of my plan to put your daughter in diapers~
You watch as Alex's expression turns from panic over the situation, to embarrassedness over her husband's blocking your way.
"Andrew!" She snaps at him. "Let Daniel up into Madison's room!" She crosses her arms disapprovingly.
Andrew blinks a few times, trying to figure out this sudden change of tone.
"Whhat do you mean?" He asks.
You try really hard to not strike a massive grin watching this, but you fail.
"I mean that he has a perfectly reasonable plan!" She grabs the rail and goes up a few steps to confront him. You become squished between the two, and so you lean against the wall. "All he wants to do is dress Maddie in a diaper. Why do you have to make this an argument??"
Andrew stares at her for a few moments.
"...sweetie what are you saying??" He shakes his head. "HOW could that be okay??"
Alex leans in a shruggy way against the rail.
"Right back at you; what isn't okay about that?"
His mouth hangs open for a second.
"...because, she would be naked!" He thrusts his hands out in questioning. "She would be wearing no clothes, and Daniel would be in the room with her, alone!"
Alex smiles.
"She wouldn't have to be alone with him at first." She says softly, clamping her hands down on her husband's.
"But...that isn't right. Sweetie please tell me you don't understand this." Andrew says, his posture increasingly weakening to his wife's reassurance. "Madison shouldn't be seen without her clothes on by anyone outside of her family. I don't understand why you're okay with this..."
"Well," Alex says, looking down at an angle, "it's just okay this time. It's okay for Daniel, alright?" She looks back up at him.
As you observe this exchange, you think about what this says about the mind control power. It seems as though Andrew did not realize you made a command to Alex, as if he didn't hear it. This would mean that your ~commands~ cannot be heard by anyone, regardless of whom the command is directed at.
Also noteworthy is how Alex doesn't even attempt to come up with a rational explanation for her endorsement of your plan; she just supports it unquestioningly. This further proves that the sapphire does not do anything you don't specifically tell it to; it doesn't effect your subjects in any way beyond what you say in your commands.
As Andrew is mulling over this most peculiar dilemma, the door from across the short hallway begins to open, and Madison steps through it.
"What are you guys talking about?" She asks, having heard her name several times.
Most likely, she had been laying on her belly the entire time, meaning that she just a few seconds ago stood up, and standing up is a position in which it's much easier to void bodily wastes. And sure enough, a wet spot starts to form in the center of her pants.
"Ope!" You exclaim. "Madison! You're wetting yourself!" Her parents look down at her pants, followed by Madison herself.
"...ahh!!" She yelps, pressing her legs together as hard as she can, putting her hand against her crotch and waddling into the corner of the hallway, managing to slow the stream down to a trickle in this very tightened pose.
You leap down the steps and rip open one of the diaper packages, pulling out a diaper and taking it up the steps.
"So, mister, do I have permission to put a diaper on your daughter?" You ask Andrew.
His eyes bob around; trying to quickly process all of this.
"WHAT?" Madison yells between the grunts, able to barely keep her eyes open and see what you're holding.
"..." Andrew looks over at Madison, and then back at you.
"...I'll do it." He says, grabbing the diaper out of your hands and turning around.
"Wait!" Alex says. "Sweetie, wait, let Daniel do it." She says, but not as firmly as before. "If you did it... that would be weird."
Andrew looks back at her, and seems to just roll his eyes and disregard her this time.
"Wait!" Alex runs up behind him and grabs the diaper. "It's not right if Daniel doesn't do it."
Madison is clenching so hard to keep her urethra closed that she's unable to respond to any of this, and it doesn't look like she's going to be able to hold it much longer. Not that it matters too much, because the little that has been escaping has already made its way down to her shins.